When a user uses a mobile terminal apparatus, an orientation of the mobile terminal apparatus held by the user is not always the same. Hence, it is desired that an orientation displayed on a display screen is rotated in accordance with the orientation held by the user.
As a method for detecting an orientation held by a user, it has been proposed as follows. By arranging noncontact sensors using infrared rays on four side surfaces of a mobile terminal apparatus, it is detected which side surface of the mobile terminal apparatus the user is facing to, that is, an orientation of the display screen viewed by the user.
However, in case where detecting a position of a user using an infrared sensor as the above-mentioned method, the occurrence possibility of a detection error tends to be high. For instance, when an object other than the user is present near the mobile terminal apparatus, there is possibility to erroneously detect the object as the user.
In Patent Literature (PLT) 1, as a method for solving the above problem, there is disclosed a display method in which information is displayed on a display screen in a desired orientation for a user by acquiring face information of the user using a digital camera function included in a mobile terminal apparatus and obtaining a relative positional relation between an orientation of the face and that of the mobile terminal apparatus.